This invention concerns manually operated winches. In particular, the invention concerns winches of the type used to secure cargo on transplant vehicles such as trucks, trailers, railcars, ships and airplanes.
When heavy or bulky cargo needs to be secured for transport, it is common to use elongated members such as chains, ropes or belts to secure the cargo in place. The elongated members are typically tightened by hand-operated winches. For example, on a trailer designed to transport automobiles, it is typical to secure each automobile by means of a chain that is tightened by a hand-operated winch. Examples of prior winches are described in U.S. Pat. Nos. 3,038,740, 5,145,299, 5,180,262, and 5,314,275, incorporated herein by this reference. Although such winches may have served their purposes, they have not been the most convenient or safe to operate.
Prior winches typically include a ratchet mechanism that can hold an elongated member taut. But, when an operator wishes to release tension on the elongated member, it is typically necessary for the operator to use one hand to operate a release lever while using the other hand to prevent the winch from free-spooling. This two-handed operation can be dangerous in cases where cargo has shifted during transit or is positioned such that it will move by gravity when the ratchet mechanism is released. For example, automobiles on transport trailers are typically positioned on ramps that are not horizontal so that gravity will urge an automobile to roll when its securing chain is detensioned. Typically, when unloading an automobile transporter vehicle, the operator must use one hand to release a winch ratchet mechanism while using the other hand to hold a handle in order to inhibit rotation of a winch spool on which the chain is wound. Thus, if an automobile begins to roll too rapidly, the operator may find it necessary to slow the movement of the automobile by resisting rotation of the winch spool single-handedly.
It can also be a problem that the release lever of a typical winch is not always easy to operate. If cargo has shifted during transit, a great deal of force may be exerted by the elongated member, which torques the shaft of the winch spool. This torque can jam elements of the ratchet mechanism into tight engagement so that a manually operated release lever is difficult to move. In such a situation, the operator may need to counter-rotate or back-off the spool a short distance in order to operate the release lever. When separate hands must be used to rotate the spool and operate the release lever, it is unnecessarily difficult to perform this operation.
Accordingly, there remains a need for winch mechanisms that can be operated easily, particularly ones that do not require the operator to use separate hands for separate operations.
Features and advantages of the present invention will be understood by reference to the following detailed description and to the drawings to which it refers.